// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/process/process_metrics.h"

#include <stddef.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include <unistd.h>

#include "base/macros.h"
#include "base/sys_info.h"

namespace base {

ProcessMetrics::ProcessMetrics(ProcessHandle process)
    : process_(process)
    , last_system_time_(0)
    , last_cpu_(0)
{
    processor_count_ = base::SysInfo::NumberOfProcessors();
}

// static
ProcessMetrics* ProcessMetrics::CreateProcessMetrics(ProcessHandle process)
{
    return new ProcessMetrics(process);
}

size_t ProcessMetrics::GetPagefileUsage() const
{
    struct kinfo_proc info;
    int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process_ };
    size_t length = sizeof(info);

    if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
        return 0;

    return info.ki_size;
}

size_t ProcessMetrics::GetPeakPagefileUsage() const
{
    return 0;
}

size_t ProcessMetrics::GetWorkingSetSize() const
{
    struct kinfo_proc info;
    int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process_ };
    size_t length = sizeof(info);

    if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
        return 0;

    return info.ki_rssize * getpagesize();
}

size_t ProcessMetrics::GetPeakWorkingSetSize() const
{
    return 0;
}

bool ProcessMetrics::GetMemoryBytes(size_t* private_bytes,
    size_t* shared_bytes)
{
    WorkingSetKBytes ws_usage;
    if (!GetWorkingSetKBytes(&ws_usage))
        return false;

    if (private_bytes)
        *private_bytes = ws_usage.priv << 10;

    if (shared_bytes)
        *shared_bytes = ws_usage.shared * 1024;

    return true;
}

bool ProcessMetrics::GetWorkingSetKBytes(WorkingSetKBytes* ws_usage) const
{
    // TODO(bapt) be sure we can't be precise
    size_t priv = GetWorkingSetSize();
    if (!priv)
        return false;
    ws_usage->priv = priv / 1024;
    ws_usage->shareable = 0;
    ws_usage->shared = 0;

    return true;
}

double ProcessMetrics::GetCPUUsage()
{
    struct kinfo_proc info;
    int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, process_ };
    size_t length = sizeof(info);

    if (sysctl(mib, arraysize(mib), &info, &length, NULL, 0) < 0)
        return 0;

    return (info.ki_pctcpu / FSCALE) * 100.0;
}

bool ProcessMetrics::GetIOCounters(IoCounters* io_counters) const
{
    return false;
}

size_t GetSystemCommitCharge()
{
    int mib[2], pagesize;
    unsigned long mem_total, mem_free, mem_inactive;
    size_t length = sizeof(mem_total);

    if (sysctl(mib, arraysize(mib), &mem_total, &length, NULL, 0) < 0)
        return 0;

    length = sizeof(mem_free);
    if (sysctlbyname("vm.stats.vm.v_free_count", &mem_free, &length, NULL, 0) < 0)
        return 0;

    length = sizeof(mem_inactive);
    if (sysctlbyname("vm.stats.vm.v_inactive_count", &mem_inactive, &length,
            NULL, 0)
        < 0) {
        return 0;
    }

    pagesize = getpagesize();

    return mem_total - (mem_free * pagesize) - (mem_inactive * pagesize);
}

} // namespace base
